Pressure-applying device



July 20, 1948. H. E. PAGE 2,445,630

PRESSURE-APPLYING DEVICE Filed Jan. 15, 1945 IN VENTOR.

Patented July 20, 1948 UNITED STATES PATENT OFFICE,

PRESSURE-APPLYING DEVICE Herbert E. Page, Alhambra, Calif.

Application January 13, 1945, Serial No. 572,688

4 Claims. 1

This invention has to do with pressure-applying devices, having as an object the provision of a device whereby two or more levers or pressureapplying members are moved relatively rapidly to apply pressure so long as the resistance to their movement does not reach a predetermined point and then the operation is automatically converted to a relatively slower movement of the levers to apply relative greater pressure to the work.

My invention also has as an object the provision of a device for selectively applying more or less pressure to work according to the resistance ofiered thereby.

Another object is the provision of a device utilizing a pair of levers to apply pressure to work positioned therebetween and wherein one of the levers yields when a predetermined resistance to their movement is reached.

My invention possesses still further and subordinate objects which will become apparent from the following explanation of one specific embodiment, for which purpose I shall refer to the accompanying drawings, in which:

Fig. 1 is a side elevation with the ends broken away and showing the device in open position; and

Fig. 2 is a view similar to Fig l. but showing the device in closed or pressure-applying position. Referring now to the drawings, I show at 5 and 6, respectively, a pair of levers which may be taken to typify any device by which work is to be accomplished by movement of the levers towards each other, the work W being positioned between the levers. For instance, the levers 5 and 6 may be considered as the cutting blades of a pair of pruning shears or as the jaws'of a pair of pliers. The levers 5v and 6 are swingably pivoted'together at their ends by means of pivot pin 1.

Lever 5 is shown as having an extension 5a to which an auxiliary lever 9 is pivoted adjacent its end by pivot pin ID, the lever 9 being in the nature of a yieldable continuation of lever 5.

A pawl I5 is pivotally secured to lever 9 between the pivot 10 and the adjacent end of said lever by a pivot pin I6, the pawl being adapted to engage the teeth of a ratchet I 8 secured to lever 6 by screws [9.

An adjustable stop screw is threadedly mounted in a threaded bracket 2| carried by the lever 5, the right-hand end of the stop screw being engageable against the pawl Hi to hold the pawl out of engagement with the ratchet when desired. The pawl is normally urged against the stop screw by means of spring secured at one end of a lateral projection 26 on the pawl and III secured at its other end to a lateral projection 27 on lever 9.

Resistance to swinging movement of lever 9 relative to lever 5 is provided by a relatively strong spring 28 which is secured at one end to a lateral projection 29 on extension 5a and secured at its other end to a lateral projection 30 on lever 9. The spring 28 may be of any desired predetermined strength.

The principles of operation as well as the cooperation of parts will be more fully understood from the following description of operation of the device. From the foregoing description it will be apparent that if the right-hand end of the lever 5 and the lever 9 are moved towards the righthand end of lever 6, the left ends of the levers 5 and 6 will be caused to move relativel rapidly towards each other into engagement with the work W. So long as no resistance to such movement is encountered which is great enough to cause yielding of the spring 28, the levers 5 and 9 Will remain in alignment as shown in Fig. 1, in which position the pawl I5 is held out of engagement with the ratchet It by the stop screw. However, if a resistance, such as the work W, is placed be tween the left-hand ends of the levers 5 and 6 which is suiflciently great to cause the spring 28 to yield, the lever 9 Will swing about pivot Illthat is, the lever 9 will break relative to lever 5which will cause the pawl to engage the ratchet teeth (see Fig. 2). Thus it will be apparent that by virtue of the relatively greater leverage thus provided. the further movement of the left-hand ends of the levers 5 and 6 towards each other will be relatively slower, but relatively greater pressure will be applied to the work by the same amount of pressure applied to the right-hand ends of the levers 9 and 6 to move them together. In accomplishing this, the levers are prevented from swinging apart by engagement of pawl IS with the ratchet teeth, while the pivoting of lever 9 about pivot point In affords substantial leverage to draw arm 6 towards arm 5 through the ratchet and pawl. While the right hand of lever 6 and lever 9 are shown as passing each other to simplify illustration, it will be understood that the handle ends may be bent to be normally more separated whereby not to pass each other during the working movement.

When the device is at rest or not in use, the auxiliary lever 9 is held against a stop pin 35 carried by the extension 5a.

It will be obvious that, in the broader aspects of my invention, other yieldable means for normally retaining levers 5 and 9 in alignment and means other than the specific pawl and ratchet may be employed to utilize the relatively greater leverage resulting from the swinging of lever 9 relative to lever 5.

Moreover, it will be apparent that my device may be used to definitely limit the maximum pressure applied to work between the levers, by eliminating the pawl and ratchet and merely allowing levers 5 and 9 to break when a resistance sufficient to cause the spring 28 to yield is encountered.

Iclaim:

1. A pressure applying device comprising a first lever and a second lever pivotally connected together between their ends for pliers-like swinging movement relative to each other, a third lever pivotally connected adjacent one end. to the second lever for swinging movement relative thereto, pawl and ratchet means cooperating with the first and third levers to swing the first and second levers towards each other in response to swinging movement of the third lever in one di-- rection relative to the second lever, and a stop on said second lever engageable with said pawl normally to hold said pawl and ratchet disengaged and operative to disengage said pawl from said ratchet in response to return of said third lever from relative motion in said one direction.

2. A pressure applying device, comprising first and second relatively movable levers pivotally connected; intermediate their ends, said second lever being relatively shorter in length than said first lever, a third lever pivotally connected to said second lever, said third lever extending in one direction from the pivot point as an extension of said second lever in opposed relation to said first lever and extending in the opposite dimotion from said pivot point as a pawl supporting arm, apawl pivotally mounted On said arm, a ratchet mounted on said first lever in cooperative relation with said pawl, a first spring urging said pawl into engagement with said ratchet, a second spring interconnecting said second lever and said third lever and yielding under predetermined resistance torelative movement between said first and second levers to permit relative swinging motion of said third lever to effect relative movement between said first and second levers with increased pressure through said pawl and ratchet, and a stop on said second lever for disengaging said pawl from said ratchet in response to the restoration or said third lever to normal position by said second spring.

3. A pressure app-lying device according to claim 2, characterized in that said stop is in the form of anadjustable set screw arranged to hold said pawl out of engagement with said ratchet against the urging of said first spring, said pawl moving out of contact with said set screw in response to pressure applying relative swinging motion of said third lever and moving into contact with said set screw in response to return motion of said third lever.

4. A pressure-applying device comprising first and second levers pivotally connected together between their ends for swinging movement relative to each other, the portions of said levers at one side of said pivotal connection constitutin pressure-receiving portions and being adapted to be moved together by compressive pressure applied thereto and the portions of said levers at the other side of said pivotal connection constituting pressure-applying portions adapted to be moved. together against work positioned therebetween in response to movement together of the first-named portions of said levers, the pressurereceiving portion of the second lever being shorter than the pressure-receiving portion of the first lever, a third lever, pivot means pivotally connecting the third lever at a point spaced from but adjacent its inner end to the pressure-receiving portion of the second lever for swinging movement relative thereto, yieldable means cooperating with the second and third levers to resist the last-named swinging movement, said yieldable means being yieldable to predetermined resistance to movement of thepressure-applying, portions of the first and second levers, means responsive to the last-named movement to move together the pressure-applying portions of the first and second levers under increased leverage, said last-named. means including a ratchet secured. to one of the first-named levers. and. a pawl carried by the third lever for engagement with the ratchet when the third lever swings relative to the second lever, and means cooperable with the pawl to hold the pawl out of engagement with the ratchet until said second and third levers swing relative to each other.

HERBERT E. PAGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Rs. 18,933 Tarbox' Sept. 5,. 1933 1,853,149 Rising Apr.,12, 1932 2,002,502 Douglas May 28,, 1935 2,410,889 Martines Nov. 12, 1946 FOREIGN PATENTS Number Country Date 42,861 Sweden July 25', 19.17 80.545 Sweden May 29, I934 

